I needed a gps for my bike, and i did not want to spend 200€ on a gps + 80€ for mounting hardware. And a iPhone holder would cost me 50€. So i decided to build one, it will work for most smart-phones as long as you can by a "case" for them.
Step 1: What you need
# You need a hi quality case, i bought mine really cheap ( 5€ ) it's a aluminium case.
# A old mountain bike reflex.
# Epoxy glue!